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Any Questions?. Chapter 5-Fundamentals of IP addressing and Routing. Overview of Network Layer Functions IP Addressing IP Routing IP Routing Protocols Network Layer Utilities. Do I know this?. Go through the Quiz- 5 minutes.

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  1. Any Questions?

  2. Chapter 5-Fundamentals of IP addressing and Routing • Overview of Network Layer Functions • IP Addressing • IP Routing • IP Routing Protocols • Network Layer Utilities

  3. Do I know this? Go through the Quiz- 5 minutes

  4. 1. Which of the following are functions of OSI Layer 3 protocols? a. Logical addressing b. Physical addressing c. Path selection d. Arbitration e. Error recovery

  5. 1. Which of the following are functions of OSI Layer 3 protocols? a. Logical addressing b. Physical addressing c. Path selection d. Arbitration e. Error recovery Answer: A & C

  6. 2. Imagine that PC1 needs to send some data to PC2, and PC1 and PC2 are separated by several routers. What are the largest entities that make it from PC1 to PC2? a. Frame b. Segment c. Packet d. L5 PDU e. L3 PDU f. L1 PDU

  7. 2. Imagine that PC1 needs to send some data to PC2, and PC1 and PC2 are separated by several routers. What are the largest entities that make it from PC1 to PC2? a. Frame b. Segment c. Packet d. L5 PDU e. L3 PDU f. L1 PDU Answer: C&E

  8. 3. Imagine a network with two routers that are connected with a point-to-point HDLC serial link. Each router has an Ethernet, with PC1 sharing the Ethernet with Router1, and PC2 sharing the Ethernet with Router2. When PC1 sends data to PC2, which of the following is true? a. Router1 strips the Ethernet header and trailer off the frame received from PC1, never to be used again. b. Router1 encapsulates the Ethernet frame inside an HDLC header and sends the frame to Router2, which extracts the Ethernet frame for forwarding to PC2. c. Router1 strips the Ethernet header and trailer off the frame received from PC1, which is exactly re-created by R2 before forwarding data to PC2. d. Router1 removes the Ethernet, IP, and TCP headers and rebuilds the appropriate headers before forwarding the packet to Router2.

  9. 3. Imagine a network with two routers that are connected with a point-to-point HDLC serial link. Each router has an Ethernet, with PC1 sharing the Ethernet with Router1, and PC2 sharing the Ethernet with Router2. When PC1 sends data to PC2, which of the following is true? a. Router1 strips the Ethernet header and trailer off the frame received from PC1, never to be used again. b. Router1 encapsulates the Ethernet frame inside an HDLC header and sends the frame to Router2, which extracts the Ethernet frame for forwarding to PC2. c. Router1 strips the Ethernet header and trailer off the frame received from PC1, which is exactly re-created by R2 before forwarding data to PC2. d. Router1 removes the Ethernet, IP, and TCP headers and rebuilds the appropriate headers before forwarding the packet to Router2. Answer: A

  10. 4. Which of the following are valid Class C IP addresses that can be assigned to hosts? a. 1.1.1.1 b. 200.1.1.1 c. 128.128.128.128 d. 224.1.1.1 e. 223.223.223.255

  11. 4. Which of the following are valid Class C IP addresses that can be assigned to hosts? a. 1.1.1.1 b. 200.1.1.1 c. 128.128.128.128 d. 224.1.1.1 e. 223.223.223.255 Answer: B

  12. 5. What is the range of values for the first octet for Class A IP networks? a. 0 to 127 b. 0 to 126 c. 1 to 127 d. 1 to 126 e. 128 to 191 f. 128 to 192

  13. 5. What is the range of values for the first octet for Class A IP networks? a. 0 to 127 b. 0 to 126 c. 1 to 127 d. 1 to 126 e. 128 to 191 f. 128 to 192 Answer: D

  14. 6. PC1 and PC2 are on two different Ethernets that are separated by an IP router. PC1’s IP address is 10.1.1.1, and no subnetting is used. Which of the following addresses could be used for PC2? a. 10.1.1.2 b. 10.2.2.2 c. 10.200.200.1 d. 9.1.1.1 e. 225.1.1.1 f. 1.1.1.1

  15. 6. PC1 and PC2 are on two different Ethernets that are separated by an IP router. PC1’s IP address is 10.1.1.1, and no subnetting is used. Which of the following addresses could be used for PC2? a. 10.1.1.2 b. 10.2.2.2 c. 10.200.200.1 d. 9.1.1.1 e. 225.1.1.1 f. 1.1.1.1 Answer: D & F

  16. 7. Each Class B network contains how many IP addresses that can be assigned to hosts? a. 16,777,214 b. 16,777,216 c. 65,536 d. 65,534 e. 65,532 f. 32,768 g. 32,766

  17. 7. Each Class B network contains how many IP addresses that can be assigned to hosts? a. 16,777,214 b. 16,777,216 c. 65,536 d. 65,534 e. 65,532 f. 32,768 g. 32,766 Answer: D

  18. 8. Each Class C network contains how many IP addresses that can be assigned to hosts? a. 65,534 b. 65,532 c. 32,768 d. 32,766 e. 256 f. 254

  19. 8. Each Class C network contains how many IP addresses that can be assigned to hosts? a. 65,534 b. 65,532 c. 32,768 d. 32,766 e. 256 f. 254 Answer: F

  20. 9. Which of the following does a router normally use when making a decision about routing TCP/IP packets? a. Destination MAC address b. Source MAC address c. Destination IP address d. Source IP address e. Destination MAC and IP address

  21. 9. Which of the following does a router normally use when making a decision about routing TCP/IP packets? a. Destination MAC address b. Source MAC address c. Destination IP address d. Source IP address e. Destination MAC and IP address Answer: C

  22. 10. Which of the following are true about a LAN-connected TCP/IP host and its IP routing (forwarding) choices? a. The host always sends packets to its default gateway. b. The host sends packets to its default gateway if the destination IP address is in a different class of IP network than the host. c. The host sends packets to its default gateway if the destination IP address is in a different subnet than the host. d. The host sends packets to its default gateway if the destination IP address is in the same subnet as the host.

  23. 10. Which of the following are true about a LAN-connected TCP/IP host and its IP routing (forwarding) choices? a. The host always sends packets to its default gateway. b. The host sends packets to its default gateway if the destination IP address is in a different class of IP network than the host. c. The host sends packets to its default gateway if the destination IP address is in a different subnet than the host. d. The host sends packets to its default gateway if the destination IP address is in the same subnet as the host. Answer: B & C

  24. 11. Which of the following are functions of a routing protocol? a. Advertising known routes to neighboring routers. b. Learning routes for subnets directly connected to the router. c. Learning routes, and putting those routes into the routing table, for routes advertised to the router by its neighboring routers. d. To forward IP packets based on a packet’s destination IP address.

  25. 11. Which of the following are functions of a routing protocol? a. Advertising known routes to neighboring routers. b. Learning routes for subnets directly connected to the router. c. Learning routes, and putting those routes into the routing table, for routes advertised to the router by its neighboring routers. d. To forward IP packets based on a packet’s destination IP address. Answer: A& C

  26. 12. Which of the following protocols allows a client PC to discover the IP address of another computer based on that other computer’s name? a. ARP b. RARP c. DNS d. DHCP

  27. 12. Which of the following protocols allows a client PC to discover the IP address of another computer based on that other computer’s name? a. ARP b. RARP c. DNS d. DHCP Answer: C

  28. 13. Which of the following protocols allows a client PC to request assignment of an IP address as well as learn its default gateway? a. ARP b. RARP c. DNS d. DHCP

  29. 13. Which of the following protocols allows a client PC to request assignment of an IP address as well as learn its default gateway? a. ARP b. RARP c. DNS d. DHCP Answer: D

  30. Any Questions?

  31. Foundation Topics • Routing: The process of forwarding packets (Layer 3 PDUs). • Logical addressing: Addresses that can be used regardless of the type of physical networks used, providing each device (at least) one address. Logical addressing enables the routing process to identify a packet’s source and destination. • Routing protocol: A protocol that aids routers by dynamically learning about the groups of addresses in the network, which in turn allows the routing (forwarding) process to work well. • Other utilities: The network layer also relies on other utilities. For TCP/IP, these utilities include Domain Name System (DNS), Dynamic Host Configuration Protocol (DHCP), Address Resolution Protocol (ARP), and ping.

  32. Network Layer Functions • Although there are lots, TCP/IP is the main one • IP Routes data packets • IP is connectionless • If a router of host can not deliver, packet is discarded without error recovery • IP wants to do as little work as possible

  33. Routing • Figuring out the next best place to send the packet

  34. Routing PC1’s Logic: Sending Data to a Nearby Router In this example, illustrated in Figure 5-1, PC1 has some data to send to PC2. Because PC2 is not on the same Ethernet as PC1, PC1 needs to send the packet to a router that is attached to the same Ethernet as PC1. The sender sends a data-link frame across the medium to the nearby router; this frame includes the packet in the data portion of the frame. That frame uses data link layer (Layer 2) addressing in the data-link header to ensure that the nearby router receives the frame.

  35. Routing • R1 and R2’s Logic: Routing Data Across the Network R1 and R2 both use the same general process to route the packet. The routing table for any particular network layer protocol contains a list of network layer address groupings. Instead of a single entry in the routing table per individual destination network layer address, there is one routing table entry per group. The router compares the destination network layer address in the packet to the entries in the routing table and makes a match. This matching entry in the routing table tells this router where to forward the packet next. The words in the bubbles in Figure 5-1 point out this basic logic.

  36. Routing • R3’s Logic: Delivering Data to the End Destination • The final router in the path, R3, uses almost the exact same logic as R1 and R2, but with one minor difference. R3 needs to forward the packet directly to PC2, not to some other router. On the surface, that difference seems insignificant. In the next section, when you read about how the network layer uses the data link layer, the significance of the difference will become obvious

  37. Network-Data Link Interaction • Each router forwards the PACKET • Each Router will create a new FRAME for the current network link

  38. Routing • The process of routing forwards Layer 3 packets, also called Layer 3 protocol data units (L3 PDU), based on the destination Layer 3 address in the packet. • The routing process uses the data link layer to encapsulate the Layer 3 packets into Layer 2 frames for transmission across each successive data link.

  39. IP Packet and header format

  40. Layer 3 Addressing • Each computer needs one network layer address • Addresses are logically grouped • Classes • Networks • Subnets • Routers only need to know the grouping information • The network or subnet address

  41. Routing Protocols • To make choices routers need • Routing table • Needs to know where the network is • Routers build the table dynamically • Use routing protocols • RIP, OSFP, IGRP, EIGRP • Routed protocols can use routers • IP • IPX/SPX

  42. IP Addressing Overview • IP v4 • 32 bit address • 4 8 bit octets • Dotted Decimal • 192.168.10.1 • 11000000.1010100.00001010.00000001 • Each network card need a unique address on its network

  43. IP address grouping • IP address are grouped by network address • Originally Class A, B and C networks • Key Ideas about network grouping • All IP addresses in the same group must not be separated by a router. • IP addresses separated by a router must be in different groups.

  44. IP Classes • Class A networks have a 1-byte-long network part. That leaves 3 bytes for the rest of the address, called the host part. • Class B networks have a 2-byte-long network part, leaving 2 bytes for the host portion of the address. • Class C networks have a 3-byte-long network part, leaving only 1 byte for the host part.

  45. IP addresses that cannot be used • All 0 in the host portion • Network address • All 1 in the host portion • Broadcast address

  46. Network Sizes

  47. IP Subnetting • Understand the idea here • Learn the math later • Divide the larger “class” networks into smaller pieces

  48. IP Subnetting • Class based address can be wasteful

  49. IP Subnetting • With Subnets we can save addresses

  50. IP Subnetting • With Subnetting we can “steal” some bits from the host portion • Allow us to redefine the Network portion of the address • Now we have Network, Host and Subnet

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